Peroxy compounds are effective bleaching agents, and compositions including mono- or di-peroxyacid compounds are useful for industrial or home laundering operations. For example, U.S. Pat. No. 3,996,152, issued Dec. 7, 1976, inventors Edwards et al., discloses bleaching compositions including peroxygen compounds such as diperizelaic acid and diperisophthalic acid.
Peroxyacids have typically been prepared by the reaction of carboxylic acids with hydrogen peroxide in the presence of sulfuric acid. For example, U.S. Pat. No. 4,337,213, inventors Marynowski et al., issued June 29, 1982, discloses a method for making diperoxyacids in which a high solids throughput may be achieved.
However, granular bleaching products containing peroxyacid compounds tend to lose bleaching activity during storage, due to decomposition of the peroxyacid. The relative instability of peroxyacid presents a problem of storage stability for compositions consisting of or including peroxyacids.
One approach to the problem of reduced bleaching activity of peroxyacid compositions has been to include "activators" for or precursors of peroxyacids. U.S. Pat. No. 4,283,301, inventor Diehl, issued Aug. 11, 1981, discloses bleaching compositions including peroxygen bleaching compounds, such as sodium perborate monohydrate or sodium perborate tetrahydrate, and activator compounds such as isopropenyl hexanoate and hexanoyl malonic acid diethyl ester. However, these bleach activators tend to yield an unpleasant odor under actual wash conditions. U.S. Pat. No. 4,486,327, inventors Murphy et al., issued Dec. 4, 1984, and U.S. Pat. No. 4,536,314, inventors Hardy et al., issued Aug. 20, 1985, disclose certain alpha substituted derivatives of C.sub.6 -C.sub.18 carboxylic acids which are said to activate peroxygen bleaches and are said to reduce malodor.
U.S. Pat. No. 4,539,130, inventors Thompson et al., issued September 3, 1985 (and its related U.S. Pat. No. 4,483,778, inventors Thompson et al., issued November 20, 1984) disclose chloro, methoxy or ethoxy subsituted on the carbon adjacent to the acyl carbon atom. U.S. Pat. No. 3,130,165, inventor Brocklehurst, issued April 21, 1964, also discloses an .alpha.-chlorinated peroxyacid, which is said to be highly reactive and unstable.
European Patent Application 166,571, inventors Hardy et al., published January 2, 1986, discloses peracids and peracid precursors said to be of the general type RXAOOH and RXAL, wherein R is said to be a hydrocarbyl group, X is said to be a hetero-atom, A is said to be a carbonyl bridging group, and L is a leaving group, such as an oxybenzene sulfonate. C.sub.6 through C.sub.20 alkyl substituted aryl are said to be preferred as R, with C.sub.6 -C.sub.15 alkyl said to be especially preferred for oxidative stability.
Various compounds have been disclosed in the prior art that contain nitrogen as part of peroxygen precursor leaving groups. Murray, U.S. Pat. No. 3,969,257, Gray, U.S. Pat. No. 3,655,567, Baevsky, U.S. Pat. No. 3,061,550, and Murray, U.S. Pat. No. 3,928,223 appear to disclose the use of acyl groups attached to nitrogen atoms as leaving groups for activators. In Finley et al., U.S. Pat. No. 4,164,395, a sulfonyl group is attached to the nitrogen atom of the leaving group. The activator structure is thus a sulfonyl oxime. Dounchis et al., U.S. Pat. No. 3,975,153 teaches the use of isophorone oxime acetate as a bleach activator. It is claimed that this isophorone derivative results in an activator of low odor and low toxicity. In Sarot et al., U.S. Pat. Nos. 3,816,319, the use of diacylated glyoximea are taught.
In sum, many different peracid activators or precursors have been proposed. However, there remain a number of problems for commercially feasible applications. Among these problems are that the known peroxygen activators and precursors have been difficult to prepare on a commercial scale, have been made from relatively expensive or toxic raw materials, have tended to yield an unpleasant odor under wash conditions, or have been found to provide impractically low yields of peroxyacid in situ.